Package com.devonfw.module.jpa.dataaccess.api

Interface GenericDao<ID,E extends com.devonfw.module.basic.common.api.entity.PersistenceEntity<ID>>

Type Parameters:

ID - is the generic type if the primary key.

E - is the generic type of the PersistenceEntity.

All Superinterfaces:

FeatureForceIncrementModificationCounter<E>

All Known Subinterfaces:

Dao<E>, MasterDataDao<E>

All Known Implementing Classes:

AbstractDao, AbstractGenericDao, AbstractMasterDataDao

public interface GenericDao<ID,E extends com.devonfw.module.basic.common.api.entity.PersistenceEntity<ID>>
extends FeatureForceIncrementModificationCounter<E>

This is the interface for a Data Access Object (DAO). It acts as a manager responsible for the persistence operations on a specific entity <E>.
This is base interface contains the CRUD operations:

• Create: call save(PersistenceEntity) on a new entity.
• Retrieve: use find* methods such as findOne(Object). More specific queries will be added in dedicated DAO interfaces.
• Update: done automatically by JPA vendor (hibernate) on commit or call save(PersistenceEntity) to merge an entity.
• Delete: call delete(PersistenceEntity) or delete(Object).

For each (non-abstract) implementation of entity MyEntity you should create an interface interface MyEntityDao that inherits from this GenericDao interface. Also you create an implementation of that interface MyEntityDaoImpl that you derive from AbstractGenericDao.

Method Summary

Modifier and Type	Method	Description
void	delete(E entity)	Deletes a given entity.
void	delete(ID id)	Deletes the entity with the given id.
void	delete(Iterable<? extends E> entities)	Deletes the given entities.
boolean	exists(ID id)	Returns whether an entity with the given id exists.
E	find(ID id)	Retrieves an entity by its id.
List<E>	findAll(Iterable<ID> ids)	Returns all instances of the type with the given IDs.
E	findOne(ID id)	Retrieves an entity by its id.
E	get(com.devonfw.module.basic.common.api.reference.Ref<ID,E> reference)
E	save(E entity)	Saves a given entity.
void	save(Iterable<? extends E> entities)	Saves all given entities.

Methods inherited from interface com.devonfw.module.jpa.dataaccess.api.feature.FeatureForceIncrementModificationCounter

forceIncrementModificationCounter

Method Detail

save

E save(E entity)

Saves a given entity. Use the returned instance for further operations as the save operation might have changed the entity instance completely.

Parameters:

entity - the entity to save

Returns:

the saved entity

save

void save(Iterable<? extends E> entities)

Saves all given entities.

Parameters:

entities - the entities to save

find

E find(ID id)

Retrieves an entity by its id.

Parameters:

id - must not be null.

Returns:

the entity with the given id or null if none found

Throws:

RuntimeException - if the requested entity does not exists (use findOne(Object) to prevent).

findOne

E findOne(ID id)
   throws IllegalArgumentException

Retrieves an entity by its id.

Parameters:

id - must not be null.

Returns:

the entity with the given id or null if none found

Throws:

IllegalArgumentException - if id is null

get

E get(com.devonfw.module.basic.common.api.reference.Ref<ID,E> reference)

Parameters:

reference - the Ref to the PersistenceEntity to get. Typically an instance of IdRef.

Returns:

the PersistenceEntity as reference for the given Ref. Will be null if the given Ref was null.

exists

boolean exists(ID id)

Returns whether an entity with the given id exists.

Parameters:

id - must not be null.

Returns:

true if an entity with the given id exists, false otherwise

findAll

List<E> findAll(Iterable<ID> ids)

Returns all instances of the type with the given IDs.

Parameters:

ids - are the IDs of all entities to retrieve e.g. as List.

Returns:

an Iterable with all entites for the given ids.

delete

void delete(ID id)
     throws IllegalArgumentException

Deletes the entity with the given id.

Parameters:

id - must not be null.

Throws:

IllegalArgumentException - in case the given id is null

delete

void delete(E entity)

Deletes a given entity.

Parameters:

entity - the entity to delete

delete

void delete(Iterable<? extends E> entities)

Deletes the given entities.

Parameters:

entities - the entities to delete